New architectures for integrated optics: low-loss tight bends and on-chip high-index-contrast potassium double Tungstate waveguides

Mustafa Sefünç

Abstract

This thesis concentrates on improving the performance of low-index-contrast waveguides in terms of reducing the bend losses and increasing the index contrast of waveguides by heterogeneous adhesive bonding and thinning. In the first part of this thesis, we have demonstrated that introducing a thin metallic layer underneath a tight bent polymer waveguide considerably reduces the bend losses, especially for transverse-electric polarization. For proof-of-concept demonstration, the proposed design is implemented on optical waveguides made of epoxy-based negative photoresist, SU-8. Alternatively, the same concept can be applied to various optical waveguide platforms that suffer from high bend losses due to a low refractive index contrast between core and cladding. The wavelength of interest in this study is 1.55 µm. The numerical study carried out in this work indicates that the introduction of a thin gold layer underneath the polymer channel blocks the radiation of the mode and pushes the confined mode back towards the core. The numerical studies and experimental realizations of such low-loss SU-8 based sharp bent waveguides, including fabrication and characterization, is covered in detail in the thesis. The second optical architecture is the on-chip, small-footprint high-index-contrast undoped/doped potassium double tungstate, KY(WO4)2, waveguides enabled by a novel fabrication technique. Up until now, the fabrication of rare-earth ion doped optical devices in potassium double tungstate material are based on growing a doped layer by liquid phase epitaxy on a bulk undoped KY(WO4)2 substrate. The resulting waveguide architecture has a low index contrast between the active layer and the undoped substrate, which leads to large dimensional cross-sections and a large pump power requirement to fully invert the amplifier core. In this thesis, a heterogeneous integration technique was proposed for the development of high-index-contrast waveguides amplifiers that can be potentially integrated on passive integration platforms. A novel fabrication procedures based on heterogeneous adhesive bonding and thinning is realized. Thin (~2 μm) layers of undoped and erbium doped potassium double tungstate, KY(WO4)2 (n~2), are successfully transferred onto SiO2 (n~1.44) substrates. The very first rib passive and active waveguides are fabricated on the transferred material by focused-ion-beam milling and argon plasma etching techniques.
Original languageEnglish
Awarding Institution
  • University of Twente
Supervisors/Advisors
  • Herek, Jennifer Lynn, Supervisor
  • García Blanco, Sonia Maria, Advisor
Date of Award15 Jun 2016
Place of PublicationEnschede
Publisher
Print ISBNs978-90-365-4139-8
DOIs
StatePublished - 15 Jun 2016

Fingerprint

waveguides
tungstates
theses
potassium
adhesive bonding
fabrication
optical waveguides
platforms
amplifiers
chips
integrated optics
argon plasma
liquid phase epitaxy
polymers
plasma etching
footprints
photoresists
erbium
rare earth elements
ion beams

Keywords

  • METIS-316999
  • IR-100512

Cite this

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title = "New architectures for integrated optics: low-loss tight bends and on-chip high-index-contrast potassium double Tungstate waveguides",
abstract = "This thesis concentrates on improving the performance of low-index-contrast waveguides in terms of reducing the bend losses and increasing the index contrast of waveguides by heterogeneous adhesive bonding and thinning. In the first part of this thesis, we have demonstrated that introducing a thin metallic layer underneath a tight bent polymer waveguide considerably reduces the bend losses, especially for transverse-electric polarization. For proof-of-concept demonstration, the proposed design is implemented on optical waveguides made of epoxy-based negative photoresist, SU-8. Alternatively, the same concept can be applied to various optical waveguide platforms that suffer from high bend losses due to a low refractive index contrast between core and cladding. The wavelength of interest in this study is 1.55 µm. The numerical study carried out in this work indicates that the introduction of a thin gold layer underneath the polymer channel blocks the radiation of the mode and pushes the confined mode back towards the core. The numerical studies and experimental realizations of such low-loss SU-8 based sharp bent waveguides, including fabrication and characterization, is covered in detail in the thesis. The second optical architecture is the on-chip, small-footprint high-index-contrast undoped/doped potassium double tungstate, KY(WO4)2, waveguides enabled by a novel fabrication technique. Up until now, the fabrication of rare-earth ion doped optical devices in potassium double tungstate material are based on growing a doped layer by liquid phase epitaxy on a bulk undoped KY(WO4)2 substrate. The resulting waveguide architecture has a low index contrast between the active layer and the undoped substrate, which leads to large dimensional cross-sections and a large pump power requirement to fully invert the amplifier core. In this thesis, a heterogeneous integration technique was proposed for the development of high-index-contrast waveguides amplifiers that can be potentially integrated on passive integration platforms. A novel fabrication procedures based on heterogeneous adhesive bonding and thinning is realized. Thin (~2 μm) layers of undoped and erbium doped potassium double tungstate, KY(WO4)2 (n~2), are successfully transferred onto SiO2 (n~1.44) substrates. The very first rib passive and active waveguides are fabricated on the transferred material by focused-ion-beam milling and argon plasma etching techniques.",
keywords = "METIS-316999, IR-100512",
author = "Mustafa Sefünç",
year = "2016",
month = "6",
doi = "10.3990/1.9789036541398",
isbn = "978-90-365-4139-8",
publisher = "Universiteit Twente",
school = "University of Twente",

}

New architectures for integrated optics: low-loss tight bends and on-chip high-index-contrast potassium double Tungstate waveguides. / Sefünç, Mustafa.

Enschede : Universiteit Twente, 2016. 124 p.

Research output: ScientificPhD Thesis - Research UT, graduation UT

TY - THES

T1 - New architectures for integrated optics: low-loss tight bends and on-chip high-index-contrast potassium double Tungstate waveguides

AU - Sefünç,Mustafa

PY - 2016/6/15

Y1 - 2016/6/15

N2 - This thesis concentrates on improving the performance of low-index-contrast waveguides in terms of reducing the bend losses and increasing the index contrast of waveguides by heterogeneous adhesive bonding and thinning. In the first part of this thesis, we have demonstrated that introducing a thin metallic layer underneath a tight bent polymer waveguide considerably reduces the bend losses, especially for transverse-electric polarization. For proof-of-concept demonstration, the proposed design is implemented on optical waveguides made of epoxy-based negative photoresist, SU-8. Alternatively, the same concept can be applied to various optical waveguide platforms that suffer from high bend losses due to a low refractive index contrast between core and cladding. The wavelength of interest in this study is 1.55 µm. The numerical study carried out in this work indicates that the introduction of a thin gold layer underneath the polymer channel blocks the radiation of the mode and pushes the confined mode back towards the core. The numerical studies and experimental realizations of such low-loss SU-8 based sharp bent waveguides, including fabrication and characterization, is covered in detail in the thesis. The second optical architecture is the on-chip, small-footprint high-index-contrast undoped/doped potassium double tungstate, KY(WO4)2, waveguides enabled by a novel fabrication technique. Up until now, the fabrication of rare-earth ion doped optical devices in potassium double tungstate material are based on growing a doped layer by liquid phase epitaxy on a bulk undoped KY(WO4)2 substrate. The resulting waveguide architecture has a low index contrast between the active layer and the undoped substrate, which leads to large dimensional cross-sections and a large pump power requirement to fully invert the amplifier core. In this thesis, a heterogeneous integration technique was proposed for the development of high-index-contrast waveguides amplifiers that can be potentially integrated on passive integration platforms. A novel fabrication procedures based on heterogeneous adhesive bonding and thinning is realized. Thin (~2 μm) layers of undoped and erbium doped potassium double tungstate, KY(WO4)2 (n~2), are successfully transferred onto SiO2 (n~1.44) substrates. The very first rib passive and active waveguides are fabricated on the transferred material by focused-ion-beam milling and argon plasma etching techniques.

AB - This thesis concentrates on improving the performance of low-index-contrast waveguides in terms of reducing the bend losses and increasing the index contrast of waveguides by heterogeneous adhesive bonding and thinning. In the first part of this thesis, we have demonstrated that introducing a thin metallic layer underneath a tight bent polymer waveguide considerably reduces the bend losses, especially for transverse-electric polarization. For proof-of-concept demonstration, the proposed design is implemented on optical waveguides made of epoxy-based negative photoresist, SU-8. Alternatively, the same concept can be applied to various optical waveguide platforms that suffer from high bend losses due to a low refractive index contrast between core and cladding. The wavelength of interest in this study is 1.55 µm. The numerical study carried out in this work indicates that the introduction of a thin gold layer underneath the polymer channel blocks the radiation of the mode and pushes the confined mode back towards the core. The numerical studies and experimental realizations of such low-loss SU-8 based sharp bent waveguides, including fabrication and characterization, is covered in detail in the thesis. The second optical architecture is the on-chip, small-footprint high-index-contrast undoped/doped potassium double tungstate, KY(WO4)2, waveguides enabled by a novel fabrication technique. Up until now, the fabrication of rare-earth ion doped optical devices in potassium double tungstate material are based on growing a doped layer by liquid phase epitaxy on a bulk undoped KY(WO4)2 substrate. The resulting waveguide architecture has a low index contrast between the active layer and the undoped substrate, which leads to large dimensional cross-sections and a large pump power requirement to fully invert the amplifier core. In this thesis, a heterogeneous integration technique was proposed for the development of high-index-contrast waveguides amplifiers that can be potentially integrated on passive integration platforms. A novel fabrication procedures based on heterogeneous adhesive bonding and thinning is realized. Thin (~2 μm) layers of undoped and erbium doped potassium double tungstate, KY(WO4)2 (n~2), are successfully transferred onto SiO2 (n~1.44) substrates. The very first rib passive and active waveguides are fabricated on the transferred material by focused-ion-beam milling and argon plasma etching techniques.

KW - METIS-316999

KW - IR-100512

U2 - 10.3990/1.9789036541398

DO - 10.3990/1.9789036541398

M3 - PhD Thesis - Research UT, graduation UT

SN - 978-90-365-4139-8

PB - Universiteit Twente

ER -